HLA Typing by Restriction Fragment Length Polymorphism Analysis

As a practical method for the identification of human leukocyte antigen (HLA) class I or II alleles, the restriction fragment length polymorphism (RFLP) approach has almost entirely been superceded by other DNA-based methods, in particular those based on polymerase chain reaction (PCR). Historically, RFLP identification of HLA class II polymorphism was important at a time when class II antisera were relatively poorly defined and B cell separation for serological typing from peripheral blood was sometimes problematic. The close correlation found between serology and RFLP pointed to the conserved organization of introns within the major histocompatibility complex (MHC), and the RFLP method quickly established that HLA and disease associations were not due to gross genomic reorganizations (insertions or deletions) in the areas examined. Some relatively recent publications have used RFLP for the identification of HLA class II polymorphism in large population studies (1 ). In this chapter, the basic method for Southern blot and the identification of RFLP will be outlined. This approach may also find application for the identification of polymorphism in new genes within the MHC and perhaps for the nonclassical HLA genes.